Interferon (IFN)-β treatment enhances CD95 and interleukin 10 expression but reduces interferon-γ producing T cells in MS patients

Interferon (IFN)-β has been shown to favorably alter the disease course of relapsing-remitting multiple sclerosis (RRMS) patients. Although its mode of action is still unclear, there is ample evidence from in vitro studies that IFN-β directly modulates the function of immune cells. We analyzed here the effects of IFN-β treatment on immune functions in vivo in a group of 25 RRMS patients who received IFN-β (8 MIU) on alternate days. At baseline and at 1, 3 and 6 months from the start of the treatment, parameters for differentiation and activation states of both monocytes and T lymphocytes were assessed. A transient increase was seen in plasma (p) interleukin (IL)-10 level whereas pIL-12 (p40) was not affected. A similar change was found in the ability of monocytes to secrete these cytokines in vitro. Notably, patients who in vitro readily responded to IFN-β with enhanced IL-10 production had the highest pIL-10 levels. Concerning T-cell differentiation, flowcytometric analysis of cytokine production showed that treatment with IFN-β moderately decreased the mean percentages of CD8 pos T cells producing IL-2 and IFN-γ and CD8 neg T cells producing IL-4 ( p